JPS6035476B2 - press mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press mechanism for dewatering a running paper web, and more particularly, the time the web passes between two opposing press rolls is long, and therefore the web is This relates to a press mechanism known as a so-called wide nip, which applies pressure for a long time.

Furthermore, the present invention provides that the web is conveyed from the forming component of the paper machine, and is conveyed in the same conveying felt so as to pass downwardly through a first wide press nip and then upwardly through a second wide press nip; It then relates to a mechanism that is transferred to a press roll forming part of a second vertical press nip.

In accordance with the present invention, the nip is configured such that the web residence time in the nip is longer than if the weep were simply passed through a pair of rolls. Conventionally, structures have been proposed for the purpose of extending the time during which pressure is applied to the web while continuously moving the web at the speed required for high-speed paper machines. Such structures have met with some success. For example, US Pat. No. 3,748,225, US Pat. No. 3,783,097, US Pat.
No. 97384, No. 3798121, No. 38047
No. 07, No. 3808092, No. 3808096, No. 3840429, and No. 3853698. The apparatus described by the above-mentioned prior patents is such that a fixed mechanical pressure on a wet paper mat is
The knowledge that the moisture in the mat is reduced to 40% or less is utilized. It is difficult to reduce moisture below 60% under the short-term dynamic pressures produced in conventional paper machines in which the web runs between a pair of nips formed by a pair of press rolls. Attempts to achieve increased dryness with conventional roll pairs have typically been made by increasing the press nip pressure.

However, a limit is quickly reached where increasing the roll load results in a relatively small loss of moisture. As is well known, dewatering is more effective in the press section of a paper machine than in the drying section of the paper machine, and if even some extra water can be removed in the press section, energy costs and installation space for the dryer drum section of the machine can be significantly reduced. A significant reduction in The difficulty of removing moisture in the press increases with increasing machine speed. This is because as the nip pressure increases, compression and crushing of the web occurs,
This is because press nip pressure is the limiting factor, resulting in high water pressure within the paper mat. The most likely way to increase the amount of water removed at high speeds is to increase the residence time of the web in the press or to increase the pressing time. Arrangements have already been provided that make press equipment more compact and reduce the mechanical framework required for wide press structures. One of the above structures is U.S. Patent No. 42016.
It is shown in No. 24. In this, the web is first conveyed through an upwardly extending wide nip and then downwardly through a continuing nip. However, such a structure has the disadvantage that it is difficult to transfer the web at high speed without damaging it, and it is difficult to avoid damage. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved high speed wide nip press mechanism which transports a web from a forming machine to a first wide press nip and then to a second wide press nip; The web is immediately transferred from this second wide press nip and run downwards so that, for example, if the web breaks, it can be easily disposed of.

As is well known to paper manufacturers, when the web is run at high speeds in modern paper machines, breakage of the web can result in significant damage. That is, a large amount of paper will accumulate, and there is a risk that mechanical parts of the paper machine will be damaged or destroyed, and there is also a risk that the life or at least the limbs of the worker operating the paper machine will be injured. That is, the present invention has a running wire that supplies the wet material to be dehydrated from the formation cross-forming section; The above-mentioned felts are sandwiched between the first cylindrical roll and the running belt, which are guided in a poisoned state. a first wide press nip extending downwardly and formed by; a first shoe extending along the first wide press nip above the running belt and pressing toward the first cylindrical roll; a turning roll that causes the first conveying felt to reversely rise and run together with the wet web; a second wide press nip that extends upward and is formed between the first conveying felt that reversely rises and the second cylindrical roll; a second shoe disposed opposite the first shoe and extending above the running belt along the second wide press nip and pressing toward the second cylindrical roll; The press mechanism is characterized in that it includes a hydraulic device that applies force to both shoes so that reactions from the two shoes cancel each other out.

Other objects, advantages and features, as well as equivalent structures and methods, are intended to be covered herein, as well as the principles of the invention in conjunction with the disclosure of the preferred embodiments, claims and drawings herein. This will become clearer with the teachings of

As shown in the drawings, the web W is formed in a forming component of the paper machine, such as between two wires of a remesh wire;
The material is conveyed from the forming mechanism on the running wire 10 and transferred to the press section. The running wire 10 moves downwards over a coach roll 11 and a turning roll 12. On the downward side of the running wire 10, the web is peeled off from the running wire by a pick-up felt or a first conveying felt 13.

A pickup equipped with a pickup castle 15 that assists in transferring the web to the lower surface of the first conveying felt 13. By means of the roller 14, the first conveying felt transfers the web from the running wire. After the web is transferred to the first conveying felt 13, the web is held between the first conveying felt 13 and the second felt 17 guided from below the first conveying felt 13, and the web is transferred to the first conveying felt 13. It is transported to a wide press nip (N-1).

The press section has a first wide press nip (N
-1) and a second wide press nib (N-2) extending upward following this.

A first wide press nip (N-1) is formed between the first outer press surfaces. This first outer pressing surface is thus provided by a cylindrical roll 18 which preferably has a second felt 17 and a relief surface in the form of an annular groove 20 . Since the web is normally completely wet in the first press section, it is recommended to use the double felt support (N-1, N-2) and the grooved cylindrical roll 18 to allow a relatively large amount of water to flow out. Because it's good. The first wide press nip is completed by its outer shoe 23.

A running belt 25 made of a strong material such as reinforced rubber used in wide nib presses passes through both press nips, guided accordingly by rolls, in particular before being introduced into the second wide press nip. It is conveyed onto a turning roll 28 following a first wide press nip. The first shoe 23 is used to generate dehydration squeezing force within the press nip.
is pressed against the press nip with a predetermined and controllable pressure. This first shoe is provided with a leading green 21. Hydraulic fluid is supplied along the entire length of the first shoe by a nozzle 26. The hydraulic fluid is conveyed through the first shoe surface and into the wide press nip. Running belt 2
5 is supported by a flowing hydraulic liquid layer. The hydraulic fluid applies pressure along the length of the first shoe from the relief lead, applying a continuous squeezing force to the running length of the web over a relatively long period of time. When the web is traveling downward in this way, hydraulic pressure is applied to the impermeable running belt 25 that squeezes the web between the two felts 13, 17 of the wide first wide press nip (N-1). is added. Following the first wide press nip, the web continues to run downward until it reaches the felt turning roll 29 where it is transferred onto only the first conveying felt.

This felt deflection roll 29 is a perforated suction roll and is provided with a suction castle 30 extending where the first conveying felt 13 is diverted from the second felt 17 to ensure transfer of the web. The web is conveyed on the first conveying felt along the turning rolls 29 and is introduced into the second wide press nip (N-2). The running belt 25 is turned and runs by a turning roll 228, and reaches the second wide press nip.

The second wide press nip has a smooth cylindrical roll 19 with a solid surface.
and a shoe 22 with a release leading green. Each shoe 22, 23 is concave so as to substantially match the curvature of the cylindrical rolls 18, 19, and is rotatably supported on roll pins 35, 36. The force of the pistons 37, 38 presses the shoe toward the press nip.
These pistons are installed in cylinders, and hydraulic pressure 40 is applied to the pressure chamber 39 between the pistons, so that the shoes 22,
Equal and opposite forces are applied to 23. Since these forces are in opposite directions, the structure supporting the shoe only needs to carry its weight, and the opposing forces creating nip pressure cancel out. A nozzle 27 is provided in front of the second shoe and directs the hydraulic fluid along its length at the relief leading green 24 of the shoe so that a flowing hydraulic layer is formed between the second wide press nip and the shoe. Downstream of the second wide press nip, the web is entrained by a smooth cylindrical roll 19 and the first conveying felt 13 runs upwards away from the smooth cylindrical roll 19.
'The web runs on top of a smooth cylindrical roll 19 and is led out of said smooth cylindrical roll by means of a separating guide roll 31.

Since the guide roll 31 is installed on the downward side of the smooth cylindrical roll 19, when the web is broken at this position, the web runs downward as shown by the dotted line web 33. A doctor blade 32 is mounted in close contact with the smooth cylindrical roll 19 on the downward side and pulls the web away from the smooth cylindrical roll in the event of a break. At the above position, the web is in an open draw (a part of the paper machine where the wet paper runs independently without any support) and is quite dry, so breakage can occur. At other locations, the web is fully supported during travel. This vertically arranged press can be relatively compact and requires a relatively small machine room. In operation, the wet web W is conveyed on the Ikeai Hosei wire, transferred to the first conveying felt 13, and then
It is supported by the second felt and conveyed downward in a double felt relationship, passing through the first wide press nip (N-1) extending vertically downward. Web felt turning roll 2
9 and is carried into the second wide press nip (N-2). If the web breaks or breaks at the turning point of the first conveying felt, the web is forced downwards so that this debris can be easily removed. The web then passes upwardly through a second vertical press nip and is transferred onto the smooth outer surface of the smooth cylindrical roll 9, from where it is removed by guide rolls 31.
If broken at this first open draw, the web will cause the pieces to travel downwardly, as illustrated by dotted line 33.
The inventor meets the aforementioned objects and advantages by providing the advantages of small skirting space, rapid squeezing of the web and improved handling in case of web breakage, and utilizes the wide press nip concept. It will be clear that an improved press mechanism has been provided.

[Brief explanation of the drawing]

The drawing is a schematic side view of a paper machine press mechanism constructed and operative in accordance with the principles of the present invention.

Claims (1)

[Claims] 1. A running wire 10 that supplies the wet web W to be dehydrated from the formation component; and a first conveying felt 13 guided into a relationship to transfer the wet web from this running wire.
and; a first cylindrical roll 1 that guides the wet web with it sandwiched between the first conveying felt and the second felt 17;
A first wide press nip (N-
1); a first shoe 21 extending above the running belt along the first wide press nip and pressing toward the first cylindrical roll; and inverting and lifting the first conveying felt together with the wet web; a second wide press nip (N-2) that extends upward and is formed between the first conveying felt that reverses and rises and the second cylindrical roll 19; a second shoe 22 disposed opposite to said running belt and extending along said second wide press nip and pressing toward said second cylindrical roll; a hydraulic device 37-38-39-40 for applying forces to both shoes in such a way that the reaction forces cancel each other out.